boil down expr/irtree/type -> lookup_rule mapping more - since lens arguments are now stored in type info, we no longer need other ways of smuggling through expression trees. also fill out new path of pointer eval single-line string generation.

src/eval/eval_ir.h

@@ -289,7 +289,6 @@ internal E_Expr *e_expr_irext_cast(Arena *arena, E_Expr *rhs, E_IRTreeAndType *r
 //~ rjf: Expression & IR-Tree => Rules
 
 internal E_LookupRule *e_lookup_rule_from_type_key(E_TypeKey type_key);
-internal E_LookupRuleExprPair e_lookup_rule_expr_pair_from_expr_irtree(E_Expr *expr, E_IRTreeAndType *irtree);
 
 #if 0 // TODO(rjf): @eval
 internal E_LookupRuleExprPair e_lookup_rule_tag_pair_from_expr_irtree(E_Expr *expr, E_IRTreeAndType *irtree);